Issues & Constraints in Job Shop Production Management

There is a large variation among job shops which are categorized as high-mix, low-volume production units. It is difficult to control and manage production for some of those shops. For more details of the variation, refer to the article, Simple and Complex High-Mix, Low-Volume (HMLV) Production Units and our web page, Intelligent Scheduling For A Tough Class of High-Mix, Low-Volume Production Systems. The difficult issues which job shop managers regularly face in complex, high-mix, low-volume production include:

  1. Job have different routings, process time requirements, priorities and due dates
  2. Make-to-order rule is necessary for a majority of jobs
  3. Final goods inventory is not to be maintained
  4. Customers demand some changes in the existing orders
  5. Hot jobs are accepted for large margins
  6. Job priorities change due to customer requirements
  7. Machines are multi-functional
  8. Workers are multi-skilled
  9. Machines breakdown and workers are absent sometimes
  10. Alternative resources are available for operations
  11. Bottlenecks keep changing over time
  12. Setup time on some machines is sequence-dependent
  13. Long operations need to be continued over many shifts with different workers in different shifts
  14. Some operations of a job can run in parallel (with or without time lag) if resources are available
  15. The total quantity of a job may be distributed to two or more similar resources at a work center
  16. Workflow of a job may resemble project workflow
  17. An operation may simultaneously require multiple resources (like machines and workers)
  18. Vendor (external) operations must be included in production schedule
  19. Actual hours of an operation may differ from the estimated hours to some extent
  20. Lead times are long and / or uncertain for some materials.

Schedlyzer efficiently addresses all the above issues in job shop scheduling while the lighter version, Schedlyzer Lite addresses the same except sequence-dependent setup times. See our approach to scheduling.